This invention relates in general to the separation of heavier materials from a fluid mixture. More specifically it relates to the separation of heavier materials from a fluid discharge mixture from hog farms to reclaim the predigested grain from hogs to clean the farms, optimize the operation, lower the oxidation time of the remaining fluids and improve the environment around hog farms. Hog farms have many environmental problems because of the outcome refuse materials which are the main cause of contamination. Usually the refuse comprises the water used to clean the pigsties and wash the hogs. This waste water mainly contains the hogs manure and the farms dirtiness which can be classified in three portions, a liquid portion, a settling solids portion and a suspended solids portion.
Generally the refuse from hog farms is treated in oxidation pits to be used thereafter in the meadows as a fertilizer without the risk of polluting the environment. In the oxidation pits the settling solids portion can be separated by dredging of the bottom of the pit. The suspended solids portion may be removed by separators and finally the liquid portion may be used alone in the meadows for irrigation, or mixed with a portion of the dried settling portion coming from the bottom of the oxidation pit to fertilize the crops.
Other methods require collecting the refuse in large tanks to separate the solids from liquids and thereafter use the removed solids coming from the bottom of the tanks to be separated into wet and dry phases by means of pumps and separators. Unfortunately, these methods are slow and laborious and require many devices and mechanisms to operate.
Screw presses used in a number of industries have been used to separate solids from liquids and the prior art teaches some methods and features to accomplish this task. For example U.S. Pat. Nos. 4,279,197 and 4,266,473 are used to dejuice grapes for wine and juice industry. U.S. Pat. No. 4,397,230 is used to separate materials with high liquid and solids content wherein the solids have varied physical characteristics with a continuous motion through the press.
U.S. Pat. No. 5,009,795 proposes a process and apparatus to separate and dewater solids contained in waste waters in concentrations of less than about 10%, like the originated in animal intensive operations or in industrial processes for processing plants or animals or their parts, mixed with fibers like animal hairs or vegetable fibers. Solids contained in waste water are separated by means of a cylindrical strainer basket and a rotary screw disposed within said basket. Waste water introduced in the separator is advanced by the screw until a solids slug develops. The slug is pressed laterally against the wall of the basket to promote removal of water. A lever mounted barrier positioned outside of solids discharge is used as a discharge control.
A huge pressure is exerted on the lateral wails of the cylindrical strainer which may cause failure of the equipment, because is a closed system. This screw press is only capable of managing concentrations of manure of up to 10% because of the principle based on exerting pressure on lateral walls.
The actual invention operates with concentrations of up to 50% of solids and can be upgraded to more than 50%, because there is no lateral pressure exerted.
U.S. Pat. No. 5.205,930 relates to a method to separate natural manure or manure from domestic animals into a wet phase and a dry phase to obtain manurial matter easier to handle. The rotatable screw conveyor includes a first and a second screw thread sections. Between the first screw thread section and the second screw thread section there is a space or annular zone free of obstruction (thread) around the entire circumference of the shaft to allow the formation of a plug of manure which will exert a back pressure on the upstream portions of manure enhancing the separation of a wet and a dry portions. Finally the second screw thread portion removes portions of the formed plug to discharge the dry phase from the device.
This screw press is unable to control the passage of manure to the discharge socket, which has to be stored in a storage room or basin for what is called liquid manure. This is a drawback of the invention because the reclaimed water needs of strong treatments to separate the remaining solids.
Another drawback of the invention is the back pressure exerted by the manure plug formed between the first and second thread sections because this kind of plugs exerts pressure on the radial walls of the screw (cylinder mantle 5) which upon variations on the water content of the manure may disalign the screw or may brake the cylinder mantle because this is a closed system.
These known methods and devices to separate manure and solids from waste waters are complicated and require sophisticated equipment. The features and advantages of the present invention overcome all these problems.
According to the foregoing it is a principal object of the invention to provide an improved horizontal solids recycler which can handle waste water with hogs manure.
It is another object of the invention to provide an inlet and distribution casing to be used under normal very low pressure flow.
It is still another object of the present invention to provide a replaceable mesh to cover a tumbler cylinder to receive a waste water curtain containing the hogs manure.
It is yet another object of the present invention to provide a device with blades to rise the solids with some moisture to a loading hopper.
It is a further object of the present invention to provide an open dewatering system with an improved self adjustable dewatering cone which drains the separated waste water back to a channel.
The horizontal solids recycler of the present invention comprises an inlet to adapt the intake to any discharge outlet to admit the waste water discharge from the farm. The inlet can be adjusted to establish a uniform curtain of waste water to be distributed over a tumbler cylinder which comprises a highly durable replaceable mesh which is around the tumbler cylinder, and rising blades to rise the solids with some moisture to pass it to a collecting bin which comprises a separator which allows the waste water to flow while the solids are transported by a screw which takes the solids to press them against a self adjustable dewatering cone. The screw is mounted outside the tumbler cylinder, over the collating bin and open to air to allow the reclaimed waste water to fall to a waste water intake which can recycle the waste water to be reused in the horizontal solids recycler. The pressing section comprises a hollowed cylinder within which the solids are pressed by the screw against a self adjustable dewatering cone to separate the remaining waste water from the solids and to transport the solids to the discharge The solids discharge from the horizontal solids recycler can be used as a feedstock for cattle or mixed again with water as a fertilizer to be used in the meadows. These and other advantages of the invention will become apparent from the following detailed description of the invention and the accompanying drawings.